I generally prefer the MAF, because it is a direct sensor. The thing the DME needs is the mass of air entering the engine at any given time. The MAP sensor does this by providing the manifold average pressure, which can then be derived into the mass present in the manifold. The AFM provides a measurement of the air flow through the manifold, (namely, the volume of air, not the mass of air) which, when combined with the temperature of the air, is translated into the mass of air in the manifold. The MAF takes a direct measurement of the mass moving through it by finding the amount of power to keep a wire, or film at a certain temperature. The heat transfer through convection is dependent on the mass flow of air (namely by the velocity and density of the air through a set aperture) which is why it doesn't have to go through a bunch of signal conditioners and complex calculations to get the data the DME needs.
In terms of performance, the AFM is generally seen as the worst option, as it has poor throttle response and cannot be re-scaled very easily if you go turbo. (the door inside it will bang open, causing a temporary lean condition, other bad things) The MAP provides a nice balance of accuracy, cost, and transient response. The MAF is more accurate and has better responsiveness, but it is more costly and has a fairly set lifespan.
With the turbo 7-er, did you go with an aftermarket kit, (Miller, TCD, Cartech) or was it a 745 mash-up?
The Br/Y should be GRD that goes to the Computer on pins 14 and 17 I think. Also, the pump only comes on when the engine is turning over. I thought the pump should briefly run with the key in the on position.
